To Margaret C.M. Smith for kindly providing the integrase clone 
 Funding support from: 
 Genome Canada/Genome Prairie 
 NSERC Discovery and Strategic Project grants

1. Production of Culture
<ol>
 <li>Prepare sterile liquid media: TY10 (5 g/l tryptone, 3 g/l yeast extract, 0.44 g/l calcium chloride dehydrate), and LB11 (10 g/l tryptone, 5 g/l yeast extract, 5 g/ sodium chloride, pH 7).</li>
 <li>Inoculate from a single colony: SmUW227 (S. meliloti LP-strain: construction will be described elsewhere, strain construction details available upon request) () into 5 ml of TY media with 50 &mu;g/ml spectinomycin. Inoculate the following strains into ...

<ol>
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C., Younger, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+motif+in+the+C-terminal+domain+of+FC31+integrase+controls+the+directionality+of+recombination.">A motif in the C-terminal domain of FC31 integrase controls the directionality of recombination.</a> Nuc. Acid. Res. 36, 3879-3891 (2008).</li><li>Campbell, R. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+monomeric+red+fluorescent+protein.">A monomeric red fluorescent protein.</a> Proc. Natl. Acad. Sci. U.S.A. 99, 7877-7882 (2002).</li><li>Schafer, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Small+mobilizable+multi-purpose+cloning+vectors+derived+from+the+Escherichia+coli+plasmids+pK18+and+pK19:+selection+of+defined+deletions+in+the+chromosome+of+Corynebacterium+glutumicum.">Small mobilizable multi-purpose cloning vectors derived from the Escherichia coli plasmids pK18 and pK19: selection of defined deletions in the chromosome of Corynebacterium glutumicum.</a> Gene. 145, 69-73 (1994).</li><li>Thorpe, H. M., Smith, M. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+site-specific+integration+of+bacteriophage+DNA+catalyzed+by+a+recombinase+of+the+resolvase&#47;invertase+family.">In vitro site-specific integration of bacteriophage DNA catalyzed by a recombinase of the resolvase&#47;invertase family.</a> Proc. Natl. Acad. Sci. 95, 5505-5510 (1998).</li><li>Jones, J. D., Gutterson, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+efficient+mobilizable+cosmid+vector,+pRK7813,+and+its+use+in+a+rapid+method+for+marker+exchange+in+Pseudomonas+fluorescens+strain+HV37a.">An efficient mobilizable cosmid vector, pRK7813, and its use in a rapid method for marker exchange in Pseudomonas fluorescens strain HV37a.</a> Gene. 61, 299-306 (1987).</li><li>Beringer, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=R+Factor+transfer+in+Rhizobium+leguminosarum.">R Factor transfer in Rhizobium leguminosarum.</a> J. Gen. Microbiol. 84, 188-198 (1974).</li><li>Lennox, E. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transduction+of+linked+genetic+characters+of+the+host+by+bacteriophage+P1.">Transduction of linked genetic characters of the host by bacteriophage P1.</a> Virology. 1, 190-206 (1955).</li><li>Hanahan, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Studies+on+transformation+of+Escherichia+coli+with+plasmids.">Studies on transformation of Escherichia coli with plasmids.</a> J. Mol. Biol. 166, 557-580 (1983).</li><li>Charles, T. C., Finan, T. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+map+of+Rhizobium+meliloti+megaplasmid+pRmeSU47b.">Genetic map of Rhizobium meliloti megaplasmid pRmeSU47b.</a> J. Bacteriol. 172, 2469-2476 (1990).</li><li>Leigh, J. A., Signer, E. R., Walker, G. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exopolysaccharide-deficient+mutants+of+Rhizobium+meliloti+that+form+ineffective+nodules.">Exopolysaccharide-deficient mutants of Rhizobium meliloti that form ineffective nodules.</a> Proc. Natl. Acad. Sci. U.S.A. 82, 6231-6235 (1985).</li><li>Heil, J. R., Nordeste, R. F., Charles, T. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+fluorescence+theatre:+a+cost-effective+device+using+theatre+gels+for+fluorescent+protein+and+dye+screening.">The fluorescence theatre: a cost-effective device using theatre gels for fluorescent protein and dye screening.</a> Can. J. Microbiol. 57, 339-342 (2011).</li><li>Datsenko, K. A., Wanner, B. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=One-step+inactivation+of+chromosomal+genes+in+Escherichia+coli+K-12+using+PCR+products.">One-step inactivation of chromosomal genes in Escherichia coli K-12 using PCR products.</a> Proc. Natl. Acad. Sci. U.S.A. 97, 6640-6645 (2000).</li><li>Lesic, B., Rahme, L. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+the+lambda+Red+recombinase+system+to+rapidly+generate+mutants+in+Pseudomonas+aeruginosa.">Use of the lambda Red recombinase system to rapidly generate mutants in Pseudomonas aeruginosa.</a> BMC Mol. Biol.. 9, 20-20 (2008).</li><li>Choi, K. -. H., Schweizer, H. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=mini-Tn7+insertion+in+bacteria+with+single+attTn7+sites:+example+Pseudomonas+aeruginosa.">mini-Tn7 insertion in bacteria with single attTn7 sites: example Pseudomonas aeruginosa.</a> Nat. Protocols. 1, 153-161 (2006).</li><li>Thomason, L. C., Calendar, R., Ow, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gene+insertion+and+replacement+in+Schizosaccharomyces+pombe+mediated+by+the+Streptomyces+bacteriophage+FC31+site-specific+recombination+system.">Gene insertion and replacement in Schizosaccharomyces pombe mediated by the Streptomyces bacteriophage FC31 site-specific recombination system.</a> Molecular Genetics and Genomics. 265, 1031-1038 (2001).</li><li>Katzen, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gateway+recombinational+cloning:+a+biological+operating+system.">Gateway recombinational cloning: a biological operating system.</a> Expert Opin. Drug Discovery. , 571-586 (2007).</li><li>Charles, T. C., Doty, S. L., Nester, E. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Construction+of+Agrobacterium+strains+by+electroporation+of+genomic+DNA+and+its+utility+in+analysis+of+chromosomal+virulence+mutations.">Construction of Agrobacterium strains by electroporation of genomic DNA and its utility in analysis of chromosomal virulence mutations.</a> Appl. Environ. Microbiol. 60, 4192-4194 (1994).</li></ol>

No conflicts of interest declared.

The IMCE technique allows for the efficient integration of a single attB flanked DNA cassette into the LP-locus of a previously engineered strain. Once the desired construct is cloned in place of rfp to create the donor cassette, the technique does not require subsequent DNA purification and transformation, making it very robust. It is critical that appropriate growth controls are included, to be certain the antibiotic resistance is due to the creation of trans-integrants and not other factors.
<p c...

<table border="1">
	<tbody>
		<tr>
			<td>Name of the reagent</td>
			<td>Company</td>
			<td>Catalogue number</td>
			<td>Comments </td>
		</tr>
		<tr>
			<td>Streptomycin</td>
			<td>Bioshop Canada Inc.</td>
			<td>STP101</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Spectinomycin</td>
			<td>Bioshop Canada Inc.</td>
			<td><a href="https://ssl34.alentus.com/bioshopcanada/detail.asp?Pin=SPE201">SPE201</a></td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Gentamicin</td>
			<td>Bioshop Canada Inc.</td>
			<td>GTA202</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Choramphenicol</td>
			<td>Bioshop Canada Inc.</td>
			<td>CLR201</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Tetracycline</td>
			<td>Bioshop Canada Inc.</td>
			<td>TET701</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Kanamycin</td>
			<td>Bioshop Canada Inc.</td>
			<td>KAN201</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Bacteriological grade agar</td>
			<td>Bioshop Canada Inc.</td>
			<td>AGR001</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Tryptone</td>
			<td>Bioshop Canada Inc.</td>
			<td>TRP402</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Yeast Extract</td>
			<td>Bioshop Canada Inc.</td>
			<td>YEX401</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Sodium Chloride</td>
			<td>Bioshop Canada Inc.</td>
			<td>SOD001</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Calcium Chloride</td>
			<td>Bioshop Canada Inc.</td>
			<td>CCL444</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>X-gluc</td>
			<td>Gold Biotechnology Inc.</td>
			<td>G1281C1</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>E. coli MT616 strain</td>
			<td>Available upon request</td>
			<td>&nbsp;</td>
			<td>Also used outside of our lab</td>
		</tr>
		<tr>
			<td>E. coli pJC2 strain</td>
			<td>In house, available by request</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>E. coli pJH110 strain</td>
			<td>In house, available by request</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>SmUW227 strain</td>
			<td>In house, available by request</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
	</tbody>
</table>

site-specific bacterial chromosome engineering: &#934;c31 integrase mediated cassette exchange (imce)

The bacterial chromosome may be used to stably maintain foreign DNA in the mega-base range1. Integration into the chromosome circumvents issues such as plasmid replication, plasmid stability, plasmid incompatibility, and plasmid copy number variance. This method uses the site-specific integrase from the Streptomyces phage (&Phi;) C312,3. The &Phi;C31 integrase catalyzes a direct recombination between two specific DNA sites: attB and attP (34 and 39 bp, respectively)4. This recombination is stable and does not revert5. A "landing pad" (LP) sequence consisting of a spectinomycin- resistance gene, aadA (SpR), and the E. coli &szlig;-glucuronidase gene (uidA) flanked by attP sites has been integrated into the chromosomes of Sinorhizobium meliloti, Ochrobactrum anthropi, and Agrobacterium tumefaciens in an intergenic region, the ampC locus, and the tetA locus, respectively. S. meliloti is used in this protocol. Mobilizable donor vectors containing attB sites flanking a stuffer red fluorescent protein (rfp) gene and an antibiotic resistance gene have also been constructed. In this example the gentamicin resistant plasmid pJH110 is used. The rfp gene6 may be replaced with a desired construct using SphI and PstI. Alternatively a synthetic construct flanked by attB sites may be sub-cloned into a mobilizable vector such as pK19mob7. The expression of the &Phi;C31 integrase gene (cloned from pHS628) is driven by the lac promoter, on a mobilizable broad host range plasmid pRK78139.
A tetraparental mating protocol is used to transfer the donor cassette into the LP strain thereby replacing the markers in the LP sequence with the donor cassette. These cells are trans-integrants. Trans-integrants are formed with a typical efficiency of 0.5%. Trans-integrants are typically found within the first 500-1,000 colonies screened by antibiotic sensitivity or blue-white screening using 5-bromo-4-chloro-3-indolyl-beta-D-glucuronic acid (X-gluc). This protocol contains the mating and selection procedures for creating and isolating trans-integrants.

Watch this Scientific Journal Video about Site-specific Bacterial Chromosome Engineering: Î¦C31 Integrase Mediated Cassette Exchange IMCE at JoVE.com

Site-specific Bacterial Chromosome Engineering: &amp;#934;C31 Integrase Mediated Cassette Exchange (IMCE)

A quick and efficient method to integrate foreign DNA of interest into pre-made acceptor strains, termed landing pad strains, is described. The method allows site-specific integration of a DNA cassette into the engineered landing pad locus of a given strain, through conjugation and expression of the &#934;C31 integrase.

Site-specific Bacterial Chromosome Engineering: &#934;C31 Integrase Mediated Cassette Exchange (IMCE)

The bacterial chromosome may be used to stably maintain foreign DNA in the mega-base range1. Integration into the chromosome circumvents issues such as ...

site-specific-bacterial-chromosome-engineering-c31-integrase-mediated

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Bioengineering

15.5K Views.  University of Waterloo. A quick and efficient method to integrate foreign DNA of interest into pre-made acceptor strains, termed landing pad strains, is described. The method allows site-specific integration of a DNA cassette into the engineered landing pad locus of a given strain, through conjugation and expression of the ΦC31 integrase.